update_source

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=true, so the safety profile is covered. The description adds the partial-update guarantee, which is real value, but it is largely a restatement of the per-field "Omit to leave unchanged" notes already in the schema, and it never explains the destructiveHint flag or what an invalid handle does.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with the action front-loaded and no filler. The second sentence is somewhat redundant with the schema's per-field notes, which keeps it from being maximally tight.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a five-parameter mutation tool with no output schema, the description covers the mutation semantics and the editable surface adequately, and the annotations carry the safety profile. It stops short of describing failure modes or what the caller gets back, but nothing critical is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and every field already carries its own 'New X. Omit to leave unchanged.' note, so the schema does the heavy lifting. The description names four of the editable fields but omits the required `source` handle, adding no meaning beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (Edit) and resource (an existing source) and enumerates the mutable fields, so an agent can distinguish it from add_source or get_source at a glance. It does not, however, distinguish itself from the generic sibling update_object_fields, which could plausibly edit the same fields.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The patch semantics ("Only the fields you provide are changed") tell the agent how to invoke the tool, which is useful implied guidance. There is no explicit statement of when to prefer this over alternatives such as update_object_fields, and no preconditions (e.g. the source must already exist) are given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.